WO2014187296A1

WO2014187296A1 - Regenerating and recycling apparatus and method for advanced treatment papermaking wastewater

Info

Publication number: WO2014187296A1
Application number: PCT/CN2014/077819
Authority: WO
Inventors: 张世文
Original assignee: 波鹰(厦门)科技有限公司
Priority date: 2013-05-19
Filing date: 2014-05-19
Publication date: 2014-11-27

Abstract

A regenerating and recycling apparatus for advanced treatment papermaking wastewater comprises a chemical decalcification system, a multi-media filtration system, an electrolysis system, a biological aerated filter (BAF), an ultrafiltration system, and a reverse osmosis system which are sequentially connected. The water concentrated by means of ultrafiltration reflows into the electrolysis system. Also provided is a regenerating and recycling method for advanced treatment papermaking wastewater. The method comprises the steps in sequence: chemical decalcification, filtration, electrolysis, biochemical processing in a biological aerated filter, ultrafiltration, and reverse osmosis. In the step of chemical decalcification, lime, NaCO₃, FeSO₄, and PAM are added to reduce the hardness of water and recover calcium carbonate. The apparatus and the method eliminate defects of high cost in by using membrane separation or absorption processing only, a good effect of papermaking wastewater treatment is obtained, and regenerated water can be recycled.

Description

Recycling and recycling device and method for papermaking advanced treatment wastewater

Technical field

The invention relates to a processing device and a method for treating waste water of papermaking, in particular to a recycling and recycling device and method for deep processing of papermaking based on chemical decalcification technology, electrochemical technology and membrane technology.

Background technique

Pulp and papermaking wastewater refers to cooking waste liquid (also known as black liquor, red liquor) produced by chemical pulping, washing and bleaching process The middle water produced in the middle and the white water produced in the papermaking process. Generally, 1t of organic matter and 400kg of alkali and sulfide are dissolved in black liquor per 1t of sulphate pulp; about 1kg of sulphite pulp is produced. Organic matter and 200kg Oxides (calcium, magnesium, etc.) and sulfides are dissolved in the red liquor. The discharge of waste liquid into rivers not only seriously pollutes the water source, but also causes a large amount of waste of resources. The paper industry is a traditional water user and one of the important sources of water pollution. At present, China's paper industry wastewater discharge and COD Emissions rank first in all types of industrial emissions in China. The paper industry has the most serious pollution to the water environment. It is not only the primary problem of pollution prevention and control in China's paper industry, but also the primary problem of national industrial wastewater treatment and water conservation. According to statistics, China's county and county-level paper and paper products industry wastewater discharge accounted for 18.6% of the country's total industrial emissions, of which the discharge discharge standard amount accounted for 49.3% of the paper industry's total wastewater discharge, COD in wastewater discharge About the national industrial COD 44.0% of total emissions. Therefore, how to eliminate the pollution of papermaking wastewater and make use of valuable resources in waste liquid is a work of great social and economic value, which should be taken seriously. With the development of the economy, China is increasingly facing the shortage of fresh water resources and the shortage of raw materials. On the other hand, water pollution is becoming more and more serious. In recent years, through the unremitting efforts of many parties, the paper industry has achieved certain results in water pollution prevention and control. Although the output of paper and paperboard has increased year by year, COD in wastewater discharge But it is decreasing year by year. However, the paper industry currently accounts for about 50% of total emissions. The wastewater has not been treated to the standard, and the recycling of papermaking wastewater is much less. Therefore, the prevention and recycling of papermaking wastewater is quite arduous.

Papermaking wastewater has complex composition and poor biodegradability. It is a difficult industrial wastewater. Its sources and characteristics are:

1. Cooking section waste liquid

That is, the black liquor produced by alkaline pulping and the red liquor produced by acid pulping. Most paper mills use alkaline pulping to produce black liquor. The pollutants contained in the black liquor account for 90% of the total pollution emissions of the paper industry. Above, and with high concentration and refractory properties, its governance has always been a major problem. The main ingredients in black liquor are 3 Species, namely lignin, polypentose and total base. Lignin is a kind of non-toxic natural high-molecular substance. It has a wide range of uses as a chemical raw material, and polypentose can be used as livestock feed.

2, middle water

The mid-stage pulping wastewater refers to the wastewater discharged from the cooking slurry after black liquor extraction in the process of screening, washing and bleaching. The color is dark yellow, accounting for 8% to 9% of the total pollution discharge of the paper industry, and the COD load of the tons of pulp is about 310kg. The middle water concentration is higher than domestic sewage, and the ratio of BOD to COD is between 0.20 and 0.35. Between the, the biodegradability is poor, the organic matter is difficult to biodegrade and the treatment is difficult. The organic matter in the middle water is mainly lignin, cellulose, organic acid, etc., to soluble COD. Mainly. Among them, the most serious environmental pollution is the chlorine-containing wastewater generated during the bleaching process, such as chlorinated bleaching wastewater and hypochlorite bleaching wastewater. Hypochlorite bleaching wastewater mainly contains chloroform and also contains 40 A variety of other organic chlorides, of which the most chlorophenols, such as dichlorophenols, trichlorophenols and the like. In addition, the bleaching waste liquid contains toxic dioxins, which are extremely toxic, posing a serious threat to the ecological environment and human health.

3, white water

White water is the papermaking section wastewater, which comes from the papermaking process in the papermaking workshop. White water mainly contains fine fibers, fillers, coatings and dissolved wood components, as well as added rubber compounds, wet strength agents, preservatives, etc., to insoluble COD. Mainly, the biodegradability is low, and the preservative added thereto has certain toxicity. White water has a large amount of water, but its organic pollution load is much lower than that of cooking black liquor and middle-stage wastewater. Almost all paper mill paper mills now use partial or fully enclosed systems to reduce paper consumption, save power, increase white water reuse, and reduce excess white water emissions.

At present, the methods used for papermaking wastewater treatment mainly include: physical filtration method, coagulation sedimentation method, adsorption method, advanced oxidation method, air floatation method, acid absorption method, catalytic oxidation method, biochemical method, etc., each method has Their respective advantages and disadvantages. Since the single treatment method is difficult to achieve the effect, in practical application, several methods are usually combined according to the actual situation of the wastewater to be treated. The typical production process is to physically treat the papermaking wastewater through filtration and then flocculation and sedimentation. After the biochemical treatment, the standard is discharged.

Chinese patent CN101708927A discloses an oxidative degradation with small investment, simple process, high pollutant removal rate and low operating cost. Advanced treatment of papermaking wastewater by flocculation and sedimentation + sand filtration. After treatment by this method, the COD was <70 mg/L, the BOD5 was <20 mg/L, and the SS was <30 mg/L.

Chinese patent CN1420091 Disclosed is an ecological treatment and resource recycling method for papermaking wastewater, which utilizes ecological engineering technology to carry out BOD5: COD in a sedimentation tank of papermaking integrated wastewater._Cr The ratio is adjusted, then enters the tandem anaerobic pond and the facultative pond for digestion, and the drainage is carried out in the conditioning tank for COD. _Cr : N : P After the ratio adjustment, multiple sets of parallel surface runoff wetlands are arranged through the water distribution system. The effluent is superior to the first-class standard for water pollutant discharge in the paper industry. It can be stored in the aerobic pond, supplemented with the water needed for the adjustment tank, and returned to the water. Surface runoff wetlands are further reprocessed. The method overcomes the disadvantages of unbalanced nutrient structure and poor biodegradability of papermaking wastewater, and can realize the ecological treatment and resource recycling of papermaking wastewater stably and effectively.

Chinese patent CN101337752 Disclosed is an advanced treatment process for papermaking wastewater, the process comprising the steps of: introducing a second-stage biochemically treated papermaking wastewater into a micro-aerated iron reduction bed, filling iron scraps in a micro-aerated iron reduction bed, and the papermaking wastewater is slightly exposed The reduction reaction is carried out in the gas-iron reduction bed; the effluent treated in the step 1 is introduced into the coagulation tank, the coagulant and the coagulant are added to the coagulation tank to promote the aggregation of the particles in the water; and the effluent after the treatment in step 2 is introduced Sediment separation is carried out in the sedimentation tank; the effluent from the sedimentation tank is introduced into the filtration tank for filtration, and the filtered effluent is sterilized and disinfected, and then introduced into the reuse water pipe network; the sludge in the sedimentation tank and the backwashing sewage in the filtration tank The sludge concentration tank is introduced and disposed of by dewatering, and the overflow liquid in the dewatering filtrate and the sludge concentration tank is introduced into the coagulation tank for further treatment. The invention has simple process, good decolorization effect and low cost.

The above methods have achieved good results in the treatment of papermaking wastewater, but there are insufficient treatment depths, and the produced water also contains more pollutants, which can only be suitable for some production processes that require less water quality. The amount of use is limited. In order to regenerate the papermaking wastewater and meet the water requirements of different production processes, especially the requirements of high quality water, it must be deeply purified. For example, the biochemical wastewater is further purified and then subjected to membrane filtration to obtain pure water. Chinese patent 201010567041.0, 201020635352.1 This paper introduces the method of membrane filtration for recycling and recycling of papermaking advanced treatment wastewater, but in the process of implementation, it is found that the calcium ion content in papermaking wastewater is as high as 150-400. Mg/L, which produces a large amount of scale, which causes serious difficulties in the regeneration of wastewater.

technical problem

The object of the present invention is to provide a chemical-based chemistry based on the problems of high cost, low efficiency, mostly treated wastewater, no deep treatment and recycling, and waste of water resources in the existing papermaking wastewater treatment method. The decalcification technology, the electrochemical technology and the membrane technology are combined, the cost is low, and the performance is high, so that the recycling and recycling apparatus and method for recycling the papermaking advanced treatment wastewater are realized.

Technical solution

The recycling and recycling device for papermaking advanced treatment wastewater according to the present invention is provided with a chemical decalcification system, a multi-media filtration system, an electrolysis system, an aerated biological filter (BAF), an ultrafiltration system and a reverse osmosis system;

The chemical decalcification system is used for removing calcium and magnesium in the papermaking advanced treatment wastewater and reducing the hardness of the water. The chemical decalcification system is provided with a coagulation tank, a shut-off valve and a inclined tube sedimentation tank, and the coagulation tank is connected with the inlet of the shut-off valve. The outlet of the shut-off valve is connected to the inlet of the inclined tube sedimentation tank, and the outlet of the inclined tube sedimentation tank is connected to the inlet of the multi-media filtration system; the mixing system in the chemical decalcification system is provided with a dispensing system and a dosing system.

The multi-media filtration system is used for filtering and separating the chemical decalcification wastewater. The multi-media filtration system is provided with a shut-off valve, a water supply pump, a multi-media filter, a backwash pump and a cleaning liquid tank; and the inlet of the shut-off valve is chemically decalcified. The outlet of the system, the inlet of the water supply pump is connected to the outlet of the shut-off valve, the outlet of the water supply pump is connected to the inlet of the multi-media filter, the outlet of the multi-media filter is connected to the electrolysis system, and the other is connected to the cleaning liquid tank by the backwashing pump.

The electrolysis system is used for electrolytic treatment of the effluent after separation and filtration of the multi-media. The electrolysis system is provided with a shut-off valve, a water supply pump and an electrolysis machine; the inlet of the shut-off valve is externally connected to the discharge port of the multi-media filter system, and the inlet of the water supply pump is connected to the outlet of the shut-off valve. The outlet of the water supply pump is connected to the inlet of the electrolysis machine, and the outlet of the electrolysis machine is connected with the inlet of the aerated biological filter (BAF).

The electrolysis machine in the electrolysis system is provided with a power source and an electrolysis cell; the electrode material in the electrolysis cell is graphite, titanium, iron, aluminum, zinc, copper, lead, nickel, molybdenum, chromium, alloy and nano catalytic inert material. In one case, the surface layer of the nano catalytic inert electrode is coated with crystal grains of 10 to 35 nm. The metal oxide inert catalytic coating, the substrate of the nano catalytic inert electrode is a titanium plate or a plastic plate.

Biological aerated filter (BAF) rapidly purifies wastewater by biooxidation degradation, and obtains papermaking purification wastewater. The biological aerated filter is equipped with a shut-off valve, a water supply pump, a water distribution system, a tank body, a packing, a blower, a shut-off valve, The pump and the water storage tank are cleaned, the inlet of the shut-off valve is connected to the outlet of the electrolysis system, the inlet of the water supply pump is connected to the outlet of the shut-off valve, the outlet of the water supply pump is connected to the inlet of the water distribution system, the water distribution system is located at the bottom of the pool body, and the packing is located in the pool body. In the middle part, the blower aerates the pool body from the bottom of the tank body, and the outlet water in the upper part of the tank body is connected with the water storage tank, and the other road is connected to the water storage tank through the washing pump and the shut-off valve.

The ultrafiltration system is used for filtering and separating the papermaking purification wastewater obtained by the aerated biological filter into dialysis water and concentrated water. The ultrafiltration system is provided with a shut-off valve, a water supply pump, an ultrafiltration membrane system, a backwashing pump, a dialysis water storage tank and a valve. The inlet of the shut-off valve is connected to the outlet of the biological aerated filter, and the outlet of the shut-off valve is connected to the inlet of the water supply pump. The outlet of the water pump is connected to the outlet of the ultrafiltration membrane system, the dialysis water outlet of the ultrafiltration membrane system is connected to the dialysis water storage tank, and the other is connected to the dialysis water storage tank by the backwashing pump, and the concentrated water of the ultrafiltration membrane system is passed through the pipeline and The valve is returned to the electrolysis system for recycling.

The ultrafiltration system further comprises an ultrafiltration membrane chemical cleaning system, the ultrafiltration membrane chemical cleaning system is used for cleaning the ultrafiltration membrane module of the ultrafiltration system, and the ultrafiltration membrane chemical cleaning system is provided with a cleaning liquid tank, a chemical cleaning pump and a shut-off valve. The outlet of the cleaning liquid tank is connected to the inlet of the chemical cleaning pump, and the outlet of the chemical cleaning pump is connected to the ultrafiltration membrane system via a shut-off valve.

The ultrafiltration system is a kind of submerged ultrafiltration, column ultrafiltration, tubular ultrafiltration, coil ultrafiltration or plate ultrafiltration, and the molecular weight cut off is 1000-100000 MWCO, and the working condition is: normal temperature~ At 45 ° C, the working pressure of immersion ultrafiltration is -1 to -50 kPa, and the working pressure of column ultrafiltration, tubular ultrafiltration, coil ultrafiltration and plate ultrafiltration is 3 to 300 kPa.

The reverse osmosis system passes the dialysis water obtained by the ultrafiltration system through the security filter and then pumps it into the reverse osmosis membrane module by the high pressure pump, and the dialysis water and the concentrated water are separated by the reverse osmosis membrane filtration, and the dialysis water enters the storage tank to obtain the reclaimed water; the concentrated water is partially concentrated. The water booster pump is recirculated for circulating membrane filtration separation, and the excess part is discharged; the reverse osmosis system is provided with a shut-off valve, a water supply pump, a security filter, a high pressure pump, a reverse osmosis membrane module and a reclaimed water storage tank, and an inlet ultrafiltration system of the shut-off valve. The outlet of the shut-off valve is sequentially passed through the water supply pump, the security filter and the high-pressure pump into the reverse osmosis membrane module, and the dialysis water outlet of the reverse osmosis membrane module is connected to the inlet of the reclaimed water storage tank;

The reverse osmosis system further comprises a reverse osmosis concentrated water recovery system, a reverse osmosis concentrated water membrane recovery system is used for recycling the concentrated water filtered by the reverse osmosis membrane, and the reverse osmosis concentrated water recovery system is provided with a reflux concentrated water pressurization system. Pump, valve and shut-off valve, reflux concentrated water booster pump inlet connected to the concentrated water outlet of reverse osmosis system, reflux concentrated water booster pump outlet connected to reverse osmosis membrane module;

The reverse osmosis system further comprises a reverse osmosis membrane cleaning regeneration system, the reverse osmosis membrane cleaning regeneration system is used for cleaning the reverse osmosis membrane module, and the reverse osmosis membrane cleaning regeneration system is provided with a cleaning liquid tank, a backwashing pump, a shut-off valve and a valve. The inlet of the cleaning liquid tank is connected to the dialysis water outlet of the reverse osmosis membrane module via a shut-off valve. The outlet of the cleaning liquid tank is connected to the concentrated water outlet of the reverse osmosis system via a shut-off valve and a valve, and the other outlet of the cleaning liquid tank is connected to the water supply pump by a backwash pump. Export.

The reverse osmosis membrane module in the reverse osmosis system is a roll membrane module, and the membrane material is an acetate membrane or a composite membrane in an organic membrane. The molecular weight cutoff of the membrane material is 50-200 MWCO, and the inlet pressure can be 6.0. ~ 45.0bar, the pressure can be 4.5 ~ 33.5 bar.

The method for recycling and recycling the papermaking advanced treated wastewater according to the present invention comprises the following steps:

(1) Chemical decalcification

After the biochemical treatment of the paper, the effluent from the secondary settling tank (ie, the papermaking advanced treatment wastewater) flows into the coagulation tank through the pipeline. In the coagulation tank, the appropriate amount of lime saturated solution is added to the 8.5 to 9.5 by stirring with the dosing device, and then added. 300~600mg/L Na ₂ CO ₃ , then add 5~10mg/L FeSO ₄ , then add Na ₂ CO _{3 to} adjust the pH to 8～9, and finally add 2~3mg/L polyphenylene amide (PAM) After the reaction is completed, it enters the inclined tube sedimentation tank to carry out sedimentation separation, thereby removing calcium and magnesium in the papermaking advanced treatment wastewater, reducing the hardness of the water, and the sediment (ie sludge) is sent to the sludge tank through the pump and the pipeline. Finally, the filter is separated in the sludge dewatering device, and the calcium carbonate is recovered, and the wastewater is filtered in the next step;

(2) Filtering

The chemically decalcified wastewater is pumped into a multi-media filter or sand filter for filtration separation to further remove SS and colloid in water;

(3) Electrolysis

Pumping the filtered wastewater into the electrolysis machine for electrolysis, degrading organic macromolecules, removing the chroma and improving the biodegradability of the wastewater. The voltage between the adjacent electrodes of the electrolyzer is 2 to 12V, and the current density is 10 to 320 mA/ Cm ² ;

(4) Biochemistry of biological aerated filter

The electrolyzed wastewater enters the aerated biological filter, and the wastewater is rapidly purified by biooxidation degradation to obtain papermaking purification wastewater;

(5) Ultrafiltration

The papermaking purification wastewater biochemically obtained from the biological aerated filter is subjected to ultrafiltration filtration to separate dialysis water and concentrated water, and the dialysis water is subjected to reverse osmosis treatment, and the concentrated water is returned to the electrolysis machine of step (2) through the pipeline for recycling;

(6) Reverse osmosis

The dialysis water obtained by ultrafiltration is filtered by security and pumped into the reverse osmosis membrane system by high pressure pump. The dialysis water and concentrated water are separated by filtration through reverse osmosis membrane. The dialysis water enters the storage tank to obtain reclaimed water; the concentrated water is partially passed through the concentrated water booster pump. The reflux is subjected to circulating membrane filtration separation, and excess is discharged.

Step (3) Electrolysis The electrolysis machine is provided with a power source and an electrolytic cell, and the electrode material in the electrolytic cell is graphite. One of titanium, iron, aluminum, zinc, copper, lead, nickel, molybdenum, chromium, alloys and nano-catalytic inert materials; the surface of the nano-catalyzed inert electrode is coated with crystal grains of 10 to 35 nm The metal oxide inert catalytic coating, the substrate of the nano catalytic inert electrode is a titanium plate or a plastic plate.

The molecular weight cut-off molecular weight of the ultrafiltration in step (5) is 1000 to 50000 MWCO, and the working condition is normal temperature~ At 45 ° C, the ultrafiltration is one of submerged ultrafiltration, column ultrafiltration, tubular ultrafiltration, coil ultrafiltration or plate ultrafiltration, and the working pressure of the submerged ultrafiltration is -1 ~ -50 kPa, while column ultrafiltration, tubular ultrafiltration, coil ultrafiltration and plate ultrafiltration have a working pressure of 3 to 300 kPa.

The reverse osmosis membrane module in the reverse osmosis in the step (6) is a roll membrane module, and the membrane material is an acetate membrane or a composite membrane in the organic membrane, and the molecular weight cutoff of the membrane material is 50 ～ 200MWCO, the inlet pressure can be 6.0 ~ 35.0bar, the pressure can be 4.5 ~ 33.5 bar.

Beneficial effect

The invention not only overcomes the defects of excessive filtration filtration treatment or adsorption treatment, but also overcomes the defects of the conventional papermaking wastewater treatment method, the waste water pollution environment and the like, and the existing papermaking advanced treatment wastewater. Purification and recycling, compared with the prior art, has the following outstanding advantages:

(1) Advanced treatment of papermaking wastewater, 70% to 85% It can be recycled and reused, which not only reduces wastewater discharge, avoids environmental pollution of wastewater, but also reduces water waste. It can also make the cost of recycled recycled water lower than the price of tap water, economically reasonable, and produce better economic benefits.

(2) The high-concentration calcium and magnesium ions in the advanced wastewater treatment can be effectively removed by the chemical decalcification system, and the removal rate is up to 50%, ensuring smooth and stable operation of the subsequent treatment process.

(3) Further reduce COD by nano-catalytic electrolysis. First, it can improve the reuse rate of wastewater, reduce wastewater discharge, avoid wastewater pollution to the environment, and reduce water waste. Second, it can kill bacteria and other microorganisms in wastewater. To eradicate the biological contamination of the subsequent ultrafiltration membrane and reverse osmosis membrane, the cleaning times of the ultrafiltration membrane and the reverse osmosis membrane are greatly reduced, the cleaning regeneration cost is reduced, the membrane use efficiency is improved, the membrane service life is prolonged, and the membrane replacement cost is reduced.

(4) Substantially reduce water consumption indicators and wastewater discharge indicators of tons of paper, and improve economic and technical indicators of enterprises.

The invention relates to the papermaking advanced treatment wastewater, which refers to the wastewater from the secondary sedimentation tank after the traditional filtration, flocculation and biochemical treatment of the papermaking wastewater, that is, the wastewater that meets the discharge standard of the third grade or above.

DRAWINGS

1 is a schematic view showing the structural composition of an embodiment of a recycling and recycling apparatus for papermaking advanced treated wastewater according to the present invention.

Figure 2 is a process flow diagram of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The invention is a design for purifying and regenerating and recycling a wastewater after deep treatment of papermaking, which is completed after in-depth systematic comparison research on the composition, properties and existing treatment schemes of the existing papermaking advanced treatment wastewater. System, multi-media filtration system, electrolysis system, aerated biological filter (BAF), ultrafiltration system and reverse osmosis system.

The invention will be further illustrated by the following examples in conjunction with the drawings.

Referring to Fig. 1, an embodiment of a recycling and utilization device for papermaking advanced treatment wastewater according to the present invention is provided with: a chemical decalcification system: a chemical decalcification system for removing calcium and magnesium in the advanced wastewater treatment, and reducing the hardness of water. The chemical decalcification system is provided with a coagulation tank 11 and a shut-off valve 12 And the inclined tube sedimentation tank 13, the coagulation tank 11 is connected with the inlet of the shut-off valve 12, the outlet of the shut-off valve 12 is connected to the inlet of the inclined tube sedimentation tank 13, and the outlet of the inclined tube sedimentation tank 13 is connected to the inlet of the multi-media filtration system;

Multi-media filtration system: The multi-media filtration system is used for filtering and separating the chemically decalcified wastewater. The multi-media filtration system is provided with a shut-off valve 21, a water supply pump 22, a multi-media filter 23, a shut-off valve 24, and a backwash pump 25 And the cleaning liquid tank 26; the inlet of the shut-off valve 21 is connected to the outlet of the chemical decalcification system, and the inlet of the water supply pump 22 is connected to the shut-off valve 21 The outlet of the water supply pump 22 is connected to the inlet of the multi-media filter 23, the outlet of the multi-media filter 23 is connected to the electrolysis system, and the other is sequentially connected to the cleaning liquid tank 25 via the backwash pump 24;

Electrolysis system: The electrolysis system is used for electrolytic treatment of the effluent after multi-media filtration separation. The electrolysis system is provided with a shut-off valve 31, a water supply pump 32 and an electrolysis machine 33; the inlet of the shut-off valve 31 is connected to a multi-media filter system discharge port, a water supply pump The inlet of 32 is connected to the outlet of the shut-off valve 31, and the outlet of the water supply pump 32 is connected to the electrolysis machine 33. The inlet of the electrolysis machine 33 is connected to the inlet of the aerated biological filter;

Biological aerated filter (BAF): Aerated biological filtration rapidly purifies wastewater by biooxidation degradation to obtain papermaking purification wastewater. The biological aerated filter is equipped with a shut-off valve 41, a water supply pump 41, a water distribution system 43, and a pool. Body 44, blower 45, packing 46, washing pump 47, shut-off valve 48, water storage tank 49, shut-off valve 41 The inlet is connected to the outlet of the electrolysis system, the inlet of the water supply pump 42 is connected to the outlet of the shut-off valve 41, the outlet of the water supply pump 42 is connected to the inlet of the water distribution system 43, and the water distribution system 43 is located at the bottom of the tank body 44, and the packing 46 Located in the middle of the pool body 44, the blower 45 aerates the pool body 44 from the bottom of the pool body 44. The outlet water in the upper part of the tank body 44 is connected to the water storage tank 49, and the other road is connected to the water storage tank 49 through the cleaning pump 47 and the shut-off valve 48 in sequence. ;

Ultrafiltration system: The ultrafiltration system is used for filtering and separating the papermaking purification wastewater obtained by the aerated biological filter into dialysis water and concentrated water. The ultrafiltration system is provided with a shut-off valve 51, a water supply pump 52, an ultrafiltration membrane system 53, a backwash pump 54, a shut-off valve 55, and a dialysis water storage tank 56. And the valve 57, the inlet of the shut-off valve 51 is connected to the outlet of the aerated biological filter, the outlet of the shut-off valve 51 is connected to the inlet of the water supply pump 52, and the outlet of the water supply pump 52 is connected to the outlet of the ultrafiltration membrane system 53, the ultrafiltration membrane system 53 The dialysis water outlet is connected to the dialysis water storage tank 56 one by one, and the other is connected to the dialysis water storage tank 56 through the backwashing pump 54 and the shutoff valve 55 in turn, and the concentrated water of the ultrafiltration membrane system 53 is passed through the valve 57. Return to the electrolysis system for reuse.

The ultrafiltration system also includes an ultrafiltration membrane chemical cleaning system, an ultrafiltration membrane chemical cleaning system for cleaning the ultrafiltration membrane module of the ultrafiltration system, and an ultrafiltration membrane chemical cleaning system with a cleaning fluid tank 61, a chemical cleaning pump 62 and a shut-off valve. 63, cleaning liquid tank 61 The outlet is connected to the inlet of the chemical cleaning pump 62, and the outlet of the chemical cleaning pump 62 is connected to the ultrafiltration membrane system 53 via the shut-off valve 63;

Reverse osmosis system: The reverse osmosis system passes the dialysis water obtained from the ultrafiltration system through the security filter and then pumps it into the reverse osmosis membrane module by high pressure pump. The dialysis water and concentrated water are separated by filtration through reverse osmosis membrane, and the dialysis water enters the storage tank to obtain reclaimed water; Part of the water is refluxed by a concentrated water booster pump for cyclic membrane filtration separation, a part of the reflux enters the electrolysis system for recycling, and the excess part is discharged; the reverse osmosis system is provided with a shut-off valve 71, a water supply pump 72, a shut-off valve 73, a security filter 74, and a membrane. System high pressure pump 75, reverse osmosis membrane module 76, shut-off valve 77 And a reclaimed water storage tank 78. The inlet of the shutoff valve 71 is connected to the outlet of the dialysis water storage tank 56 of the ultrafiltration system, and the outlet of the shutoff valve 71 is sequentially passed through the water supply pump 72, the shutoff valve 73, the security filter 74 and the membrane system high pressure pump 75. Entering the reverse osmosis membrane module 76, the dialysis water outlet of the reverse osmosis membrane module 76 is connected to the inlet of the reclaimed water storage tank 78 via a shut-off valve 77;

Reverse osmosis concentrated water recovery system: The reverse osmosis concentrated water recovery system is a system for filtering reverse osmosis membrane filtered concentrated water. The reverse osmosis membrane recovery system is provided with a reflux concentrated water booster pump 81. Reflux concentrated water booster pump 81 The inlet is connected to the concentrated water outlet of the reverse osmosis membrane module 76, and the outlet of the reflux concentrated water booster pump 81 is connected to the inlet of the reverse osmosis membrane module 76;

Reverse osmosis membrane cleaning and regeneration system: reverse osmosis membrane cleaning and regeneration system is used for cleaning reverse osmosis membrane module. Reverse osmosis membrane cleaning and regeneration system is provided with shut-off valve 91, cleaning fluid tank 92, shut-off valve 93, shut-off valve 94, backwashing pump 95 Globe valve 96 And valve 97. The inlet of the cleaning liquid tank 92 is connected to the dialysis water outlet of the reverse osmosis membrane module 76 via a shut-off valve 91. The outlet of the cleaning liquid tank 92 is connected to the reverse osmosis membrane module 76 via a shut-off valve 93 and a valve 97. The concentrated water outlet, the other outlet of the cleaning liquid tank 92 passes through the shutoff valve 94 and is connected to the outlet of the water supply pump 72 via the backwash pump 95 and the shutoff valve 96.

Embodiments of the invention

The invention is a design for purifying and regenerating and recycling the waste water after deep treatment of the papermaking after the in-depth systematic comparative study on the composition, properties and existing treatment schemes of the existing papermaking advanced treatment wastewater, which is through chemical decalcification The combination of electrolysis, membrane filtration and other methods to form a purification and regeneration recycling method that is particularly suitable for wastewater treatment of advanced papermaking.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIG.

Example 1

Recycling and recycling method for 500 tons/day papermaking advanced treatment wastewater.

The water quality indicators of the papermaking advanced treatment wastewater are determined as shown in Table 1.

Table 1 Water quality indicators of wastewater treatment wastewater

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	150 150	44	色度 Chroma		60 60
22	SS SS	mg/L Mg/L	140 140	55	Ca Ca	mg/L Mg/L	200 200
33	电导率 Conductivity	μS/cm μS/cm	1800 1800	66	硬度 Hardness	mmol/L Mmmol/L	44

(1) Chemical decalcification

The papermaking advanced treatment wastewater flows into the coagulation tank through the pipeline. In the coagulation tank, the appropriate amount of saturated lime solution is added to the 8.5 by the dosing device to adjust the pH to 8.5, then 600 mg/L of Na ₂ CO _{3 is} added, and then 10 mg/ L FeSO ₄ , then add Na ₂ CO _{3 to} adjust the pH to 8 and finally add 2mg/L polyphenylene amide (PAM). After the reaction is completed, enter the inclined tube sedimentation tank and carry out sedimentation separation to remove the papermaking depth. Calcium and magnesium in the wastewater, reducing the hardness of the water, the sediment (ie sludge) is sent to the sludge tank through the pump and pipeline, and finally filtered and separated in the sludge dewatering device, and the calcium carbonate is recovered, and the wastewater enters the next step. Step filtration;

(2) Filtering

The chemically decalcified wastewater is pumped into a multi-media filter for filtration separation to further remove SS and colloid in water;

(3) Electrolysis

The filtered wastewater is pumped into the electrolysis machine for electrolysis, degrading organic macromolecules, removing the chroma and improving the biodegradability of the wastewater. The voltage between the adjacent electrodes of the electrolysis machine is 2V, and the current density is 10 mA/cm ² ;

(4) Biochemistry of biological aerated filter

(5) Ultrafiltration

The papermaking purification wastewater biochemically obtained from the biological aerated filter is subjected to immersion ultrafiltration filtration, and the dialysis water and the concentrated water are separated, and the dialysis water enters the reverse osmosis treatment, and the concentrated water is returned to the electrolysis machine through the pipeline for recycling;

(6) Reverse osmosis

The immersion ultrafiltration working conditions are: normal temperature ~ 45 ° C, working pressure is -1 to -50 kPa The reverse osmosis membrane module is a roll membrane module, and the membrane material is an acetate membrane in an organic membrane, the inlet pressure can be 6.0 to 45.0 bar, and the outlet pressure can be 4.5 to 33.5 bar.

The above ultrafiltration is immersion ultrafiltration, and the ultrafiltration may be one of immersion ultrafiltration, column ultrafiltration, tubular ultrafiltration, roll ultrafiltration or plate ultrafiltration.

The water quality indicators of reclaimed water were determined as shown in Table 2.

Table 2 Water quality indicators of reclaimed water

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	10 10	44	色度 Chroma		10 10
22	SS SS	mg/L Mg/L	≤ 1≤ 1	55	Ca Ca	mg/L Mg/L	≤1 ≤1
33	电导率 Conductivity	μS/cm μS/cm	100 100	66	硬度 Hardness	mmol/L Mmmol/L	0.1 0.1

Example 2

Recycling and recycling of wastewater treated by 6000 tons/day of papermaking.

The water quality indicators of the papermaking advanced treatment wastewater are determined as shown in Table 3.

Table 3 Water quality indicators of wastewater treatment wastewater

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	90 90	44	色度 Chroma		150 150
22	SS SS	mg/L Mg/L	60 60	55	Ca Ca	mg/L Mg/L	160 160
33	电导率 Conductivity	μS/cm μS/cm	1200 1200	66	硬度 Hardness	mmol/L Mmmol/L	2 2

(1) Chemical decalcification

The papermaking advanced treatment wastewater flows into the coagulation tank through the pipeline. In the coagulation tank, the appropriate amount of saturated lime solution is added to the pH value to 9.5 by stirring, and then 300 mg/L of Na ₂ CO _{3 is} added, and then 5 mg/ L FeSO ₄ , then add Na ₂ CO _{3 to} adjust the pH to 9, and finally add 2mg / L polyphenylene amide (PAM), after the reaction is complete, enter the inclined tube sedimentation tank, and carry out sedimentation separation, thereby removing the papermaking depth treatment Calcium and magnesium in the wastewater, reducing the hardness of the water, the sediment (ie sludge) is sent to the sludge tank through the pump and pipeline, and finally filtered and separated in the sludge dewatering device, and the calcium carbonate is recovered, and the wastewater enters the next step. Step filtration;

(2) Filtering

The chemically decalcified wastewater is pumped into a sand filter to be separated by filtration to further remove SS and colloid in water;

(3) Electrolysis

The sand filtered and filtered wastewater is pumped into the electrolysis machine for electrolysis, degrading organic macromolecules, removing chroma and improving the biodegradability of the wastewater. The voltage between the adjacent electrodes of the electrolysis machine is 6V, and the current density is 320mA/cm. ² ;

(4) Biochemistry of biological aerated filter

(5) Ultrafiltration

The papermaking purified wastewater obtained by biochemistry of the biological aerated filter is subjected to column ultrafiltration filtration, and the dialysis water and the concentrated water are separated, and the dialysis water enters the reverse osmosis treatment, and the concentrated water is returned to the electrolysis machine of the step (2) through the pipeline for recycling.

(6) Reverse osmosis

The tubular ultrafiltration working condition is: normal temperature ~ 45 ° C, working pressure is 3 ~ 300 kPa The reverse osmosis membrane module is a roll membrane module, the membrane material is a composite membrane, the inlet pressure can be 6.0-45.0 bar, and the outlet pressure can be 4.5-33.5 bar.

The above ultrafiltration is tubular ultrafiltration. Ultrafiltration can be one of submerged ultrafiltration, column ultrafiltration, tubular ultrafiltration, coil ultrafiltration or plate ultrafiltration.

The reclaimed water quality indicators are determined as shown in Table 4.

Table 4 Water quality indicators of reclaimed water

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	66	44	色度 Chroma		55
22	SS SS	mg/L Mg/L	≤ 1 ≤ 1	55	Ca Ca	mg/L Mg/L	≤ 1 ≤ 1
33	电导率 Conductivity	μS/cm μS/cm	8080	66	硬度 Hardness	mmol/L Mmmol/L	0.05 0.05

Example 3

Recycling and recycling method for 20000 tons/day papermaking advanced treatment wastewater.

The water quality indicators of the papermaking advanced treatment wastewater are determined as shown in Table 5.

Table 5 Water quality indicators of wastewater treatment wastewater

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	120120	44	色度 Chroma		8080
22	SS SS	mg/L Mg/L	120120	55	Ca Ca	mg/L Mg/L	200200
33	电导率 Conductivity	μS/cm μS/cm	15001500	66	硬度 Hardness	mmol/L Mmmol/L	1.21.2

(1) Chemical decalcification

The papermaking advanced treatment wastewater flows into the coagulation tank through the pipeline. In the coagulation tank, the appropriate amount of saturated lime solution is added to the pH by the dosing device under stirring, and then 500 mg/L of Na ₂ CO _{3 is} added, and then 8 mg/ L FeSO ₄ , then add Na ₂ CO _{3 to} adjust the pH to 8.5, and finally add 3mg / L polyphenylene amide (PAM), after the reaction is completed, enter the inclined tube sedimentation tank, and carry out sedimentation separation, thereby removing the papermaking depth treatment Calcium and magnesium in the wastewater, reducing the hardness of the water, the sediment (ie sludge) is sent to the sludge tank through the pump and pipeline, and finally filtered and separated in the sludge dewatering device, and the calcium carbonate is recovered, and the wastewater enters the next step. Step filtration;

(2) Filtering

(3) Electrolysis

The filtered wastewater is pumped into the electrolysis machine for electrolysis, degrading organic macromolecules, removing the chromaticity, and improving the biodegradability of the wastewater. The voltage between the adjacent electrodes of the electrolysis machine is 12V, and the current density is 200 mA/cm ² ;

(4) Biochemistry of biological aerated filter

(5) Ultrafiltration

The papermaking purified wastewater obtained by biochemistry of the biological aerated filter is subjected to tubular ultrafiltration filtration to separate dialysis water and concentrated water, and the dialysis water is subjected to reverse osmosis treatment, and the concentrated water is refluxed through the pipeline to the step (2) recycling machine;

(6) Reverse osmosis

The tubular ultrafiltration working condition is: normal temperature ~ 45 ° C, working pressure is 3 ~ 300 kPa The reverse osmosis membrane module is a roll membrane module, the membrane material is a composite membrane, the inlet pressure can be 6.0 to 45.0 bar, and the outlet pressure can be 4.5 to 33.5 bar.

The reclaimed water quality indicators are determined as shown in Table 6.

Table 6 Water quality indicators of reclaimed water

序号 Serial number	项目 Project	单位 Unit	测定值 measured value	序号 Serial number	项目 Project	单位 Unit	测定值 measured value
11	COD_Cr COD _Cr	mg/L Mg/L	88	44	色度 Chroma		66
22	SS SS	mg/L Mg/L	≤ 1 ≤ 1	55	Ca Ca	mg/L Mg/L	≤ 1 ≤ 1
33	电导率 Conductivity	μS/cm μS/cm	6060	66	硬度 Hardness	mmol/L Mmmol/L	0.060.06

Industrial applicability

The invention not only overcomes the defects of excessive filtration filtration treatment or adsorption treatment, but also overcomes the defects of the conventional papermaking wastewater treatment method, the waste water pollution environment and the like, and the existing papermaking advanced treatment wastewater. Purification and recycling With good industrial applicability.

Claims

A recycling and recycling device for papermaking advanced treatment wastewater, characterized by comprising a chemical decalcification system, a multi-media filtration system, an electrolysis system, an aerated biological filter (BAF), an ultrafiltration system and a reverse osmosis system;

The chemical decalcification system comprises a coagulation tank, a shut-off valve and a inclined tube sedimentation tank, the coagulation tank is connected with the inlet of the shut-off valve, the outlet of the shut-off valve is connected to the inlet of the inclined tube sedimentation tank, and the outlet of the inclined tube sedimentation tank is connected with the multi-media The inlet of the filtration system;

The multi-media filtration system is provided with a shut-off valve, a water supply pump, a multi-media filter, a backwash pump and a cleaning liquid tank; the inlet of the shut-off valve is connected to the outlet of the chemical decalcification system, and the inlet of the water supply pump is connected to the outlet of the shut-off valve for supply The outlet of the water pump is connected to the inlet of the multi-media filter, the outlet of the multi-media filter is connected to the electrolysis system, and the other is connected to the cleaning liquid tank by the backwashing pump;

The electrolysis system is provided with a shut-off valve, a water supply pump and an electrolysis machine, the inlet of the shut-off valve is externally connected to the discharge port of the multi-media filter system, the inlet of the water supply pump is connected to the outlet of the shut-off valve, the outlet of the water supply pump is connected to the inlet of the electrolysis machine, and the electrolysis machine is The outlet is connected to the inlet of the biological aerated filter (BAF);

The biological aerated filter (BAF) is provided with a shut-off valve, a water supply pump, a water distribution system, a pool body, a packing, a blower, a shut-off valve, a washing pump, a water storage tank, an inlet of the shut-off valve, an outlet of the electrolysis system, and a water supply pump. The inlet of the inlet valve is connected to the outlet of the water supply pump, and the outlet of the water supply pump is connected to the inlet of the water system. The water distribution system is located at the bottom of the pool body, and the packing is located in the middle of the pool body. The blower is aerated from the bottom of the pool body, and the water outlet in the upper part of the tank body is all the way. Connected to the water storage tank, the other way is connected to the water storage tank by the cleaning pump and the shut-off valve;

The ultrafiltration system is provided with a shut-off valve, a water supply pump, an ultrafiltration membrane system, a backwashing pump, a dialysis water storage tank and a valve, an inlet of the shut-off valve is connected to an outlet of the biological aerated filter, and an outlet of the shut-off valve is connected to the water supply pump. Import, the outlet of the water supply pump is connected to the outlet of the ultrafiltration membrane system, the dialysis water outlet of the ultrafiltration membrane system is connected to the dialysis water storage tank, and the other is connected to the dialysis water storage tank by the backwashing pump. The concentrated water of the ultrafiltration membrane system is Pipes and valves are returned to the electrolysis system for recycling;

The reverse osmosis system is provided with a shut-off valve, a water supply pump, a security filter, a high pressure pump, a reverse osmosis membrane module and a reclaimed water storage tank. The inlet of the shut-off valve is connected to the outlet of the ultrafiltration system, and the outlet of the shut-off valve is sequentially supplied by the water supply pump and the security guard. The filter and the high pressure pump enter the reverse osmosis membrane module, and the dialysis water outlet of the reverse osmosis membrane module is connected to the inlet of the reclaimed water storage tank.
According to claim 1 The apparatus for regenerating recycling of papermaking advanced treatment wastewater is characterized in that: the ultrafiltration system further comprises an ultrafiltration membrane chemical cleaning system, and the ultrafiltration membrane chemical cleaning system is provided with a cleaning liquid tank, a chemical cleaning pump and a shut-off valve. The outlet of the cleaning liquid tank is connected to the inlet of the chemical cleaning pump, and the outlet of the chemical cleaning pump is connected to the ultrafiltration membrane system via a shut-off valve.
According to claim 1 The apparatus for regenerating recycling of papermaking advanced treatment wastewater is characterized in that: the reverse osmosis system further comprises a reverse osmosis concentrated water recovery system, and the reverse osmosis concentrated water recovery system is provided with a reflux concentrated water booster pump, and reflux concentrated The water booster pump inlet is connected to the concentrated water outlet of the reverse osmosis system, and the reflux concentrated water booster pump outlet is connected to the reverse osmosis membrane module.
According to claim 1 The apparatus for regenerating recycling of papermaking advanced treatment wastewater is characterized in that: the reverse osmosis system further comprises a reverse osmosis membrane cleaning and regeneration system, and the reverse osmosis membrane cleaning and regeneration system is provided with a cleaning liquid tank and a backwashing pump, The shut-off valve and the valve, the inlet of the cleaning liquid tank is connected to the dialysis water outlet of the reverse osmosis membrane module via the shut-off valve, and the outlet of the cleaning liquid tank is connected to the concentrated water outlet of the reverse osmosis system through the shut-off valve and the valve, and the other outlet of the cleaning liquid tank is The backwash pump is connected to the water supply pump outlet.
According to claim 1 The recycling and recycling device for papermaking advanced treatment wastewater is characterized in that: the mixing tank in the chemical decalcification system is provided with a dispensing system and a dosing system.
As in claim 1 The invention relates to a recycling and recycling device for papermaking advanced treatment wastewater, characterized in that: in the electrolysis system, the electrolysis machine is provided with a power source and an electrolytic cell, and the electrode materials in the electrolytic cell are graphite, titanium, iron, aluminum, One of zinc, copper, lead, nickel, molybdenum, chromium, alloys and nanocatalytic inert materials.
Claim 6 The apparatus for regenerating and recycling waste water of a papermaking advanced treatment, characterized in that: the surface layer of the nano catalytic inert electrode is coated with crystal grains of 10 to 35 nm The metal oxide inert catalytic coating, the substrate of the nano catalytic inert electrode is a titanium plate or a plastic plate.
According to claim 1 The invention relates to a recycling and recycling device for papermaking advanced treatment wastewater, characterized in that: the ultrafiltration system has a molecular weight cutoff of 1000-00000 MWCO, and the working condition is: normal temperature to 45 ° C, and the ultrafiltration system is an immersion type super Filter, column ultrafiltration, tubular ultrafiltration, coil ultrafiltration or plate ultrafiltration, immersion ultrafiltration working pressure is -1 ~ -50kPa, column ultrafiltration, tubular ultrafiltration, coil Ultrafiltration and plate ultrafiltration work at 3 ~ 300kPa.
According to claim 1 The invention relates to a recycling and recycling device for papermaking advanced treatment wastewater, characterized in that: the reverse osmosis membrane module in the reverse osmosis system is a wound membrane module, and the membrane material is an acetate membrane or a composite membrane in an organic membrane, and a membrane The molecular weight cutoff of the material is 50 ~ 200MWCO, the inlet pressure can be 6.0 ~ 45.0bar, the pressure can be 4.5 ~ 33.5bar.
A method for recycling and recycling waste water of papermaking treatment, which comprises the following steps:

(1) Chemical decalcification

After the biochemical treatment of the paper, the effluent from the secondary settling tank (ie, the papermaking advanced treatment wastewater) flows into the coagulation tank through the pipeline. In the coagulation tank, the appropriate amount of lime saturated solution is added to the 8.5-9.5 by stirring with the dosing device, and then added. 300~600mg/L Na 2 CO 3 , then add 5~10mg/L FeSO 4 , then add Na 2 CO 3 to adjust the pH to 8～9, and finally add 2~3mg/L polyphenylene amide (PAM) After the reaction is completed, it enters the inclined tube sedimentation tank to carry out sedimentation separation, thereby removing calcium and magnesium in the papermaking advanced treatment wastewater, reducing the hardness of the water, and the sediment (ie sludge) is sent to the sludge tank through the pump and the pipeline. Finally, the filter is separated in the sludge dewatering device, and the calcium carbonate is recovered, and the wastewater is filtered in the next step;

(2) Filtering

The chemically decalcified wastewater is pumped into a multi-media filter or sand filter for filtration separation to further remove SS and colloid in water;

(3) Electrolysis

The filtered wastewater is pumped into the electrolysis machine for electrolysis, degrading organic macromolecules, removing the chromaticity, and improving the biodegradability of the wastewater. The voltage between the adjacent electrodes of the electrolysis machine is 2 to 12 V, and the current density is 10 to 320 mA/ Cm 2 ;

(4) Biochemistry of biological aerated filter

The electrolyzed wastewater enters the aerated biological filter, and the wastewater is rapidly purified by biooxidation degradation to obtain papermaking purification wastewater;

(5) Ultrafiltration

The papermaking purification wastewater biochemically obtained from the biological aerated filter is subjected to ultrafiltration filtration to separate dialysis water and concentrated water, and the dialysis water is subjected to reverse osmosis treatment, and the concentrated water is returned to the electrolysis machine of step (2) through the pipeline for recycling;

(6) Reverse osmosis

The dialysis water obtained by ultrafiltration is filtered by security and pumped into the reverse osmosis membrane system by high pressure pump. The dialysis water and concentrated water are separated by filtration through reverse osmosis membrane. The dialysis water enters the storage tank to obtain reclaimed water; the concentrated water is partially passed through the concentrated water booster pump. The reflux is subjected to circulating membrane filtration separation, and excess is discharged.
Claim 10 The method for recycling and recycling the papermaking advanced treated wastewater, characterized in that: in the step (3), the electrolyzer is provided with a power source and an electrolytic cell, and the electrode material in the electrolytic cell is graphite, titanium, iron, One of aluminum, zinc, copper, lead, nickel, molybdenum, chromium, alloys, and nanocatalytic inert materials.
Claim 11 The method for recycling and recycling waste water of a papermaking advanced treatment, characterized in that: the surface layer of the nano catalytic inert electrode is coated with crystal grains of 10 to 35 nm The metal oxide inert catalytic coating, the substrate of the nano catalytic inert electrode is a titanium plate or a plastic plate.
The method for recycling and recycling waste water of an advanced papermaking process according to claim 10, wherein the molecular weight cut-off molecular weight of the ultrafiltration in step (5) is 1000 to 50000 MWCO, and the working condition is normal temperature. At 45 ° C, the ultrafiltration is one of submerged ultrafiltration, column ultrafiltration, tubular ultrafiltration, coil ultrafiltration or plate ultrafiltration, and the working pressure of the submerged ultrafiltration is -1 ~ -50 kPa, while column ultrafiltration, tubular ultrafiltration, coil ultrafiltration and plate ultrafiltration have a working pressure of 3 to 300 kPa.
According to claim 10 The method for recycling and recycling waste water of a papermaking advanced treatment, characterized in that: the reverse osmosis membrane module in the reverse osmosis in step (6) is a roll membrane module, and the membrane material is an acetate membrane or a composite membrane in an organic membrane. The membrane, the membrane material has a molecular weight cut off of 50 to 200 MWCO, a feed pressure of 6.0 to 35.0 bar, and a pressure of 4.5 to 33.5 bar.